1. Field of the Invention
The present invention relates to a hardenable material which comprises a substrate carrying a hardenable resin, for example which hardens on contact with water. More specifically, this invention relates to a colored orthopaedic splinting material which carries a hardenable resin.
2. Description of Related Art
It is well established to use water hardenable isocyanate functional resins in orthopaedic splint bandages. Such bandages are disclosed in British Patent No. GB2216533.
For some considerable time now it has been desirable to use colored casting materials which includes for example solid colours, prints and multicolored decorations. Methods of colouring casting materials are disclosed in U.S. Pat. No. 5,476,438. However such casts suffer from the disadvantage that the colored prepolymers will readily stain other material with which they come into contact. Methods of overcoming this disadvantage are disclosed in European Patent Application No. 479269 and PCT Application No. WO93104709. Both applications generally relate to the manufacture of colored orthopaedic casts or multicolored orthopaedic casts by printing one or more pigments onto the surface of a knitted substrate which results in the coating or partial coating of some of the yarns but not the individual filaments. In addition, such printing techniques prove to be expensive in manufacture, inter alia, because of the need to clean machinery when changing production from one color to another. It is also a method which does not lend itself well to continuous production and generally requires a batch process.
A preferred material from which casting substrates can be formed are glass fibre yarns. Glass fibre yarns are conventionally manufactured by drawing molten glass through nozzles to form filaments. The filaments are cooled, sized and gathered to form glass fibre strands. The glass fibre strands are subsequently twisted and plied to form glass fibre yarns.